Stopping power and straggling of energetic light ion beams in yttrium

Energy loss and straggling for protons, deuterons and α-particles in yttrium were measured in the energy region between 0.15 MeV and 2.5 MeV. The measured stopping powers of the hydrogen ions agree reasonably well with the semi-empirical values of Andersen and Ziegler, although better agreement was found with the values of Janni. For helium ions there are a marked difference with the values of Ziegler. Below 200 keV/amu the stopping ratios of the helium and hydrogen ions are lower than Ziegler's master curve. The straggling values of the hydrogen ions are about 15% lower than the Bohr estimate, while the straggling of the helium ions reach the Bohr value at about 0.2 MeV/amu.     

Photoluminescence measurements of LiF TL detectors

The properties of standard lithium fluoride (LiF) thermoluminescent (TL) detectors, which are routinely used in radiation protection systems, were investigated under light stimulation. The luminescence of different types of LiF detectors, which were irradiated with gamma rays of energy up to 300 Gy and alpha particles with a fluence up to 5*10⁹ cm⁻², were stimulated by a blue light and were heated up to temperature of 240 °C or 400 °C, depending on the type of detectors. The irradiated LiF detectors during the blue-light (460 nm) stimulation emit green photoluminescence (PL) with a wavelength of 530 nm. The LiF detectors showed a PL effect of much higher efficiency after they were irradiated with alpha particles than after they were irradiated with gamma rays. However, in contrast to PL, the TL readout showed a significantly lower efficiency of LiF detectors after alpha particle irradiation. These effects result from the different trap mechanisms that are responsible for TL and PL phenomena. The temperature stability of the traps responsible for the PL effect for both types of LiF detectors was studied.     

High-accuracy fluence determination in ion beams using fluorescent nuclear track detectors

We present an approach to use Al₂O₃:C,Mg-based fluorescent nuclear track detectors (FNTDs) and confocal laser scanning microscopy as a semiautomatic tool for fluence measurements in clinical ion beams. The method was found to cover a linear energy transfer (LET) range from at least L_∞(Al₂O₃) = 0.5 keV/μm to 61,000 keV/μm with a detection efficiency ≥99.83% (20 MeV protons) at particle fluences up to at least 5 × 10⁷ per cm². Our technique allows to determine the spatial fluence distribution on a microscopic scale and enables detailed track-by-track comparison studies between different fluence detectors.     

Experimental approaches to crystalline ion beams

Facing the difficulties associated with the preparation of crystalline ion beams in heavy ion storage rings we propose two complementary table top schemes to elucidate fundamental issues like stability criteria for moving ion crystals at low velocities. One is based on a small radio-frequency quadrupole (RFQ) storage ring, where by laser cooling Mg⁺ ion crystals at rest were observed, but conceptionally modified with additional acceleration electrodes and manufactured with highest mechanical precision. The other approach suggested here implies the use of an RFQ ion guide for the lateral confinement of the ions combined with buffer gas viscous damping, which could lead to an ideal starting condition for first time direct three-dimensional laser cooling in a single pass arrangement. This revised version was published online in July 2006 with corrections to the Cover Date.     

Relative thermoluminescent efficiency of LiF detectors for proton radiation: Batch variability and energy dependence

The available experimental data on the relative thermoluminescent efficiency of the LiF:Mg,Ti dosimetric peaks for protons are contradictory. There are several reports showing that the efficiency exceeds unity by even more than 30%, however, many others show the efficiency close to unity or even lower. These contradictory data might be a result of the real variability of TLD properties or of not perfectly reproduced experimental conditions.In an attempt to resolve this issue, the efficiency of 16 batches of LiF:Mg,Ti (MTS) detectors for 60 MeV protons produced at the IFJ Kraków over the last 20 years was measured. All values of the relative TL efficiency were found to exceed unity significantly, with an average of 1.09. Dispersion between different batches was very low, all data were within 4% of the mean value.In second part of experiment the dependence of the relative efficiency of LiF:Mg,Ti and LiF:Mg,Cu,P detectors on proton energy was determined. The efficiency for LiF:Mg,Ti dosimetric peaks was found to have a maximum of 1.20 at about 20 MeV. For LiF:Mg,Cu,P the relative efficiency decreases systematically with decreasing proton energy, from 0.96 at 56 MeV, to 0.61 at 11 MeV.     

Surface structure studies of Cl adsorption on Ag{001} using energetic ion beams

Angle-resolved SIMS experiments have been employed to study the bonding geometry of Cl on Ag{001}. The procedure was to bombard the target with 2 or 3 keV Ar⁺ ions in the low dose mode at various incident angles and to measure the desorption of Ag⁺ or Cl⁻ ions at various detection angles. For the case of the c(2 × 2)-Cl/Ag{001} structure, azimuthal angle distributions of both Ag⁺ and Cl⁻ ions indicate that the Cl atom binds in the four-fold hollow site. Measurement of the polar angle distributions suggests that the Cl overlayer is above the surface plane, ruling out the formation of an epitaxial AgCl layer. The Ag---Cl bond-length was determined to be 2.60 ± 0.04 Å using shadow-cone enhanced desorption. With this measurement the angle of incidence of the ion beam is varied until the shadow-cone created by a target Cl atom intersects a nearby Ag atom. The result is in agreement with earlier LEED experiments.     

Spatial structure and energy spectrum of ion beams studied with CN detectors within a small PF device

The paper reports the application of Solid-State Nuclear Track Detectors to study the pulsed plasma-ion streams emitted from plasma-focus (PF) type discharges, which were performed within a low-energy PACO device constructed at Instituto de Fisica Arroyo Seco. The PACO device was operated under static initial gas conditions or with dynamic gas puffing. Studies of the structure of the fast deuteron beams were carried out within an energy range from 80 keV to about 2 MeV. Studies of ion energy and an ion angular distribution were also performed. The measurements showed that the fast deuterons are emitted in many “narrow” micro-beams, as in other larger PF devices. The anisotropy of the deuteron angular distribution was explained by the stochastic character of the formation of local ion sources within the PF discharge column.     

High energy beta beams without massive detectors

In this paper, the possibility to exploit a high energy beta beam without massive detectors is discussed. The radioactive ions are boosted up to very high with the neutrino beam pointing towards an instrumented surface located at a moderate baseline (e.g. from CERN to the Gran Sasso Laboratories). oscillations and their CP conjugate are tagged as an excess of horizontal muons produced in the rock and tracked by the low-mass instrumented surface installed in one of the LNGS experimental halls. We show that the performance of this complex for what concerns the determination of the angle of the leptonic mixing matrix is comparable with the current low- design based on a gigantic water Cherenkov at Frejus.Received: 13 September 2004, Published online: 9 November 2004PACS: 14.60.Pq, 14.60.Lm     

Absorption cycles. A review with regard to energetic efficiency

The improvement of energy conversion systems in order to decrease consumption of primary energy and to minimize negative impact on the environment which originates from industries with large cooling and heating demand is mandatory. We want to review the potential of absorption heat pump technology in this respect. Absorption systems are compared to conventional compression systems with regard to the consumption of primary energy. Different areas of application such as air-conditioning, refrigeration, heating, combined cooling and heating, and process heat recovery are treated. Absorption systems have a large potential for energy saving, especially when they are operated by heat from cogeneration systems or, of course, by waste heat. But even direct-fired systems can compete with compression machinery: highly efficient cycles which perform far better than comparable conventional machines are in development.     

Multicomponent vacuum-arc ion beams

The paper generalizes the results of research on pulsed-periodic generation of multicomponent ion streams in sources based on vacuum arc discharge. Methods are considered for forming composition-and-energy controlled multicomponent beams for multielement ion implantation in Raduga sources. The features and laws governing the emission properties of wide-aperture ion sources with plasma generation by evaporation of a material in a cathode spot are discussed. A comparative analysis is made of the physical laws and possibilities of forming one-element or multielement ion beams during extraction from a free plasma boundary under conditions when a virtual anode exists and a positive voltage drop near the anode exists in the vacuum-arc-discharge plasma.Scientific-Research Institute of Nuclear Physics at the Tomsk Polytechnical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 34–52, March, 1994.     

Pulsed high-current ion beams

Conclusions The review which has been conducted of the contemporary state of high-current ion technology permits making the following estimate of the prospects for each of the trends of HCIB generation for specific goals. It is evident that magnetically insulated diodes providing multiple operating conditions and maximum HCIB voltages are more preferable for the realization of inertial CTF. At the same time the low-impedance mode condition of the triode is preferable for use in equipment with plasma heating.In the final analysis, the future of each of the HCIB generation technologies discussed in the plan for their utilization for CTF or a different area of science and engineering will depend on their economic profitability.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 83–105, October, 1979.In conclusion, the author apologizes for papers which have been omitted from this review, which is due to the limited scope of the review and the unavoidable lag of any review behind the pace of completed investigations.     

托卡马克装置中高能离子的直接损失

通过严格求解导心坐标系下的哈密顿方程,提出了托卡马克装置中离子的真实轨道理论,并利用此理论对国际热核聚变实验堆(ITER)中α离子的真实轨道进行了数值模拟研究,获得了驻点轨道和近期理论预言的半俘获轨道.根据此真实轨道理论计算了ITER中α离子的直接损失率.结果发现,与所提出的真实轨道理论相比,以前的回旋平均理论大幅度低估了α离子的直接损失率,两种理论的损失率差值可达14%,对此差异进行了详细的分析并给出了物理上的解释.     

含能离子盐的太赫兹光谱研究

在传统硝基含能材料研究的基础上,进一步探索含能离子盐类物质的太赫兹波谱特性,拓宽太赫兹波技术在安全检测领域的应用研究范围,对新型含能离子盐(5-ATN,BMDATHBT)进行了太赫兹时域光谱和傅里叶变换红外光谱的实验测量,得到样品在0.5～8.0 THz范围内的吸收频谱.基于密度泛函理论,采用Gaussian 03及M...     

Application of solid-state nuclear track detectors for studies of fast ion beams within PF-1000 and other plasma-focus facilities

The paper presents results of studies of the fast ion emission from two plasma facilities: PF-1000 and PF-II. The measurements were carried out mainly with solid-state nuclear track detectors (SSNTDs). To register ion mass- and energy-spectra, obtained when primary ion beams are deflected by magnetic and electric fields of a Thomson-type spectrometer, the SSNTDs plates were installed inside the analyzer. To measure ion angular distributions the SSNTDs were located within the main discharge chamber, at different angles to the electrode axis. The SSNTDs were also applied to register ion beam images formed within an ion pinhole camera, and to determine a spatial location of the fast ion sources.     

Laser acceleration of ion beams

We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g., by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams can provide additional acceleration to gold ions of the order of GeV/nucleon. The text was submitted by the authors in English.     

Energy response of the TL detectors based on YAlO3:Mn crystals

This study demonstrates the energy response of thermoluminescent (TL) detectors based on YAlO₃:Mn crystals. Experimental results of the relative sensitivity of YAlO₃:Mn²⁺ detectors to various kinds of photon radiation (from ⁶⁰Со, ¹³¹Cs, ¹⁹²Ir, and ¹³⁷Cs isotopes; X-ray from 220 kVp; and photon radiation from a linear accelerator (LINAC) at 5, 10, and 15 MV) agree with the theoretical energy response from Monte Carlo simulation. In addition to YAlO₃ (YAP), energy response was calculated for other yttrium-containing oxides such as Y₂O₃, Y₃Al₅O₁₂ (YAG), and Y₄Al₂O₉ (YAM). A possibility of filtering (modification) of the energy response of high atomic number (Z) materials by the metallic filters was shown.